Fecal Metabolomic Signatures in Colorectal Adenoma Patients Are Associated with Gut Microbiota and Early Events of Colorectal Cancer Pathogenesis

Abstract

Colorectal adenomas are precancerous lesions of colorectal cancer (CRC) that offer a means of viewing the events key to early CRC development. A number of studies have investigated the changes and roles of gut microbiota in adenoma and carcinoma development, highlighting its impact on carcinogenesis. However, there has been less of a focus on the gut metabolome, which mediates interactions between the host and gut microbes. Here, we investigated metabolomic profiles of stool samples from patients with advanced adenoma (n = 102), matched controls (n = 102), and patients with CRC (n = 36). We found that several classes of bioactive lipids, including polyunsaturated fatty acids, secondary bile acids, and sphingolipids, were elevated in the adenoma patients compared to the controls. Most such metabolites showed directionally consistent changes in the CRC patients, suggesting that those changes may represent early events of carcinogenesis. We also examined gut microbiome-metabolome associations using gut microbiota profiles in these patients. We found remarkably strong overall associations between the microbiome and metabolome data and catalogued a list of robustly correlated pairs of bacterial taxa and metabolomic features which included signatures of adenoma. Our findings highlight the importance of gut metabolites, and potentially their interplay with gut microbes, in the early events of CRC pathogenesis. IMPORTANCE Colorectal adenomas are precursors of CRC. Recently, the gut microbiota, i.e., the collection of microbes residing in our gut, has been recognized as a key player in CRC development. There have been a number of gut microbiota profiling studies for colorectal adenoma and CRC; however, fewer studies have considered the gut metabolome, which serves as the chemical interface between the host and gut microbiota. Here, we conducted a gut metabolome profiling study of colorectal adenoma and CRC and analyzed the metabolomic profiles together with paired microbiota composition profiles. We found several chemical signatures of colorectal adenoma that were associated with some gut microbes and potentially indicative of future CRC. This study highlights potential early-driver metabolites in CRC pathogenesis and guides further targeted experiments and thus provides an important stepping stone toward developing better CRC prevention strategies.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

“…Insufficient human studies have evaluated the metabolome and microbiota in relation to adenomas. Findings from a recent study suggest that there is a correlation between bacterial dysbiosis, the metabolome, and colorectal adenomas [ 92 ]. More studies are required to fully explore the correlation between microbiota, metabolome, and ACP.…”

“…In fact, the microbiota influences the host through their metabolites. Kim and his collaborators found that, in patients with ACP, a high concentration of bioactive lipids, including polyunsaturated fatty acids, sphingolipids, and secondary bile acids, existed [ 92 ]. All these compounds are produced by the bacteria species that are dominant (in number) in patients with adenomas and CRC.…”

Traditional Chinese Medicine and Gut Microbiome: Their Respective and Concert Effects on Healthcare

“…2020 (Kim et al, 2020) Non-nucleatum Fusobacteria common in southern Chinese populations are associated with colorectal cancer:…”

Identification of MicroRNA-Target Gene-Transcription Factor Regulatory Networks in Colorectal Adenoma Using Microarray Expression Data

“…Colorectal adenoma (CRA) is defined as non-cancerous lesion of the large intestinal epithelium. It is commonly acknowledged that CRA is a precancerous condition and may progress to colorectal cancer (CRC) that is a common reason of cancer death worldwide, with the unknown etiology and pathogenesis (Fearon, 2010;Kim et al, 2020). In spite of certain progress recently, the understanding of underlying biomolecules of CRA is rather rudimentary and the process of screening these biomolecules is still continuing.…”